Horatio allen



-UNITED sTATEs PATENT oEEIoE.

HORATIO ALLEN, OF NEV YORK, N. Y.

GUT-OFF-VALVE GEAR OF STEAM-ENGINES.

Specification of Letters Patent No.

To all whom 'it may concern:

Be it known that I, HoRATIo ALLEN, of the city, county, and State of NewYork, have invented an Improvement in Cut-Off- Valve Gear ofSteam-Engines, of which the following is a full, clear, and eXactspecification.

The improvements described herein, are improvements on the cut-ocombinations, patented by Horatio Allen, February 6th, 1849; and SamuelH. Gilman, December 10th, 1850. By reference to the specilication anddrawings of those patents, it will be seen that the steam valve israised by means of a loose toe, and returned to its seat by lowering, orby tripping the loose toe.

It is the object of the present improvement to provide a control of thefall of the toe, after it is tripped; this is effected by connectingwith the end of the toe, a piston or plunger operating in a chambercontaining water or other fluid, the outlet of the Huid from the chamberbeing of such area as will provide an adequate controlling resistance.

The drawings herewith represent the combination.

A, is the shaft which carries the loose toe; it may be an independentshaft or the rock shaft which carries the exhaust toe. See Figures l and2.

B, is the loose toe by which the lifter C is raised.

D, is a reservoir in which is placed the controlling chamber E. In thischamber operates the plunger F. This plunger is connected with the endof the toe B by the rod G.

H, is a valve opening into the controlling chamber, and I, is an outletfrom the controlling chamber, the area of which can be adjusted by thestop valve K.

The operation of this combination is as follows: The reservoir D, isnearly filled with water, oil, or other fluid. When the toe is raised,it lifts the plunger and the vacuum thus produced in the controllingchamber is filled from the reservoir through the valve H. When the toeis tripped, the fall of the toe carries down the plunger, the valve Hcloses, and the liuid can only escape by the outlet I. As the toe falls,the leverage with 18,837, dated December 15, 1857.

which the pressure on the toe acts to force the fluid through the outletbecomes of less and less length, and as the toe reaches a position justbefore the steam valve is seated, the leverage becomes very small, andthe motion of the toe is controlled by the diminished power to force thefluid through the outlet. The toe may be raised and tripped in variousways. In thev one represented, an arm L fastened on the rock shaft,carries the pin M, on which the pawl N drops into gear by suitablenotch. lVhen the pawl is thrown out of gear, the toe is tripped andfalls as fast as the controlling plunger will permit.

The controlling chamber could be provided with a supply valve and outletin other ways than that represented, without changing its mode ofoperation. A very compact arrangement is one where a piston is used; thesupply valve is in the bottom of the piston, and the outlet is throughthe center of the valve. In this form no reservoir is required, thechamber forming the reservoir and the Huid passing alternately fromabove to below the piston and from below to above the piston.

The toe could be controlled just as it reached the position of seatingt-he valve by substituting for the plunger and controlling chamber thedash pot with secondary chamber, the parts being so adjusted that theresistance created by the secondary chamber should come into action atthe proper time.

I do not claim the use of a controlling chamber or dash pot to break thefall of the valve as they have long been used in connection with valvegear; but

I claim- As an improvement on the cut-off valve gear patented by HoratioAllen, February 9th, 1849, and by Samuel H. Gilman, December 10th, 1850,the combination of a plunger operating to force a fluid through an oriceor of the dash pot with secondary chamber, with the loose toe wherebythe fall of the toe when tripped is controlled, substantially in themanner and for the purpose set forth.

HORATIO ALLEN.

Witnesses E. LEvERIoH, '.IHos. FITZPATRicK.

